Renewable fuse plug



March 1, 1938. s. DERDZINSKI 2,109,901

RENEWABLE FUSE PLUG Filed May 10, 1935 IZ'g- Patented Mar. 1, 1938UNITED STATES PATENT OFFICE 1Claim.

My invention refers to renewable fuse plugs, and it has for its primaryobject to provide a removable eiement for such plugs capable of beingreadily slipped into place for renewal by those 5 unskilled in the art,the same comprising a onepiece ductile element, having spade endsconnected by a narrow looped strip, to thus permit ready adjustment intocontact clips, and to also permit expansion and contraction between thecontact spade ends, which expansion is necessary in a practical device,dueto thermal changes.

Obviously the invention is particularly designed to permit ready renewalof old plugs, whereby the cost of entire new structures is eliminated,which is true under existing normal conditions after a plug fuse hasburned out. In other words, it is not necessary to even remove the fuseplug from the fuse box, but upon observation of a blowout, a new elementis readily adjusted into position after the closure cap of the plug isremoved.

With the above and other minor objects in view, the invention consistsin certain peculiarities in construction andarrang ement of parts, aswill be hereinafter more particularly set forth with reference to theaccompanying drawing:

Figure 1 represents asectional elevation of the plug embodying thefeatures of my invention, the view being upon a magnified scale, thesection line being indicated by line l-l of Figure 2.

Figure 2 is a plan view of the plug.

Figure 3 is a detailed sectional elevation of one of the terminalsshowing the coupling jaw and element therein, the element being insection as indicated by line 3-3 of Figure 1.

36 Figure 4 is a face view of the fuse element.

Referring by characters to the drawing, A represents a standard screwplug having a removable apertured cap B and a mica closure disc 0. Theplug is provided with the usual metallic ter- 40 minals l andi, theirupper ends I being folded upon themselves to form spring jaws adapted toreceive a one-piece element or fuse strip, which strip comprises a pairof spade ends 4-4 connected by a narrow strip 5, which strip portion isductile and intermediately bowed to form a loop 5. By this constructionof fuse elements, it will be observed that the spade ends can be readilyinserted into the contact jaws 33, whereby a positive and ample contactis effected 5 between the terminals l and 2. Furthermore, due to thefact that the strip is ductile, the spade element can be adjustedlongitudinally, whereby perfect contact is effected, and thereafter thenarrow strip 5 will assume a loop, as shown, to permit ready expansionand contraction, and also to provide the desired length of fuse element.

From the foregoing description, it will be observed that when the fusestrip blows out, across the narrow strip portion, this blow-out can bereadily observed by an inspection of the plug, and thereafter to renewthe entire plug apparatus the operator will simply remove the cap andmica disc, whereby access is had to the hollow shell portion into which-is nested the jaw elements. A new strip is then inserted, and thebroken line is immediately renewed at a comparatively nominal expense.

While I have shown and specifically described a standard fuse plug toillustrate my invention, it is obvious that the structural features maybe varied within the scope of the claim.

I claim:

In a renewable fuse plug, a body of insulation, 3 a metallic shell onthe outer face of said body, a pair of flat conductor strips arranged inspaced parallel relation in said body, the inner end of one strip beingelectrically connected to the shell, the inner end of the other stripbeing extended through the inner end of the body to form a centralcontact, the outer ends of both of said strips being bifurcated forminglegs, said legs being twisted at right-angles to the body portions ofthe strips and back upon themselves in facing 40 relation-to form springterminals, and a fuse link detachably fitted between said facing bentback spring terminals.

STANLEY DERDZINSKI.

